jump.hs

{-# LANGUAGE ScopedTypeVariables #-}

import System.Environment (getArgs, getEnv)
import Control.Exception (catch, SomeException)
import Data.Map.Strict (fromList, lookup, findWithDefault, insert, assocs)
import Prelude hiding (lookup)

partitionPairs' Nothing ys (x:xs) = partitionPairs' (Just x) ys xs
partitionPairs' Nothing ys [] = ys
partitionPairs' (Just x) ys (y:xs) = partitionPairs' Nothing ((x,y):ys) xs
partitionPairs' (Just _) ys [] = error "corrupt ~/.jumphs"

partitionPairs = partitionPairs' Nothing []

updateBookmarks bookmarks _ [] = bookmarks
updateBookmarks bookmarks bookmark [dir] = insert bookmark dir bookmarks

main = do
  args@(bookmark:xs) <- getArgs
  jumpdb <- fmap (++ "/.jumphs") $ getEnv "HOME"
  bookmarks <- readFile jumpdb `catch` (\(_ :: SomeException) -> return "")
  bookmarks <- return $ fromList $ partitionPairs $ lines bookmarks
  bookmarks <- return $ updateBookmarks bookmarks bookmark xs
  bookmarks `seq` writeFile jumpdb $ unlines $ Prelude.map (\(a,b) -> a++"\n"++b) $ assocs bookmarks
  putStrLn $ findWithDefault "" bookmark bookmarks